1. Field of the Invention
This invention relates to exit devices using latch mechanisms mortised into a door, particularly mortise latch locks used with built-in lighted signage. More specifically, the invention relates to mortise latch locks with illuminated signage within the trim plate. The illuminated signage may be toggled ON or OFF to signal an occupied/unoccupied status, such as with a lavatory door.
2. Description of Related Art
Mortise latch locks are used in a variety of door locations and applications, often on several doors within a single room. Currently, there are no indications on the lock themselves for signaling which of the doors is the best means of egress from a room in an emergency. Moreover, mortise locks are becoming more commonly used on the doors that lead to a building's stairwells. Consequently, there exists a need to have mortise locks display signage, especially during emergency situations.
While mechanically actuated products exist to indicate the locked/unlocked status of the mortise lock, for example, the occupied/unoccupied status of a room, or designate an egress pathway, there are no electrically operated mortise locks that have illuminating signs and supporting electronics built within the lock or trim plate. Furthermore, the existing mechanical products are generally difficult to see from long distances or in low light situations. One problem regarding implementing an illuminated sign in a mortise lock trim plate is space. Typical trim plates are extremely thin, making it impractical to size any incandescent bulb(s) between the thin trim plate and the door face. A second issue is the availability of a sufficient power source for incandescent lights or other light sources, such as laser diodes and the like. Incandescent lights will normally drain batteries in a relatively short time, requiring either frequent replacement or a direct hard-wire to the power grid.
Due to the higher power requirements for incandescent lights as opposed to electroluminescent strips, heat dissipation has been a problem in the prior art when trying to integrate signage. The power required to illuminate light bulbs, and the light bulb illumination itself, will heat the trim plate until it becomes too hot to touch. Introducing electroluminescent strips into the trim plate design relieves the heat dissipation, since the electroluminescent strip requires less power to operate, and does not radiate as much heat energy as the incandescent lamps.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a mortise latch lock with illuminating signage built into the lock trim plate.
It is another object of the present invention to provide illuminating signage for mortise locks that does not overheat the lock, and is efficient enough to work on battery power if required.
A further object of the invention is to provide a mortise latch lock with an illuminated sign capable of designating when the lock is activated and when it is deactivated.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.